1. Field of the Invention
The present invention relates to an improved swinging ladder dredge apparatus that employs a ladder that is supported by a dredge hull and in part by a floating or flotation traveling tank that pivots with the ladder and wherein the tank travels between ladder end portions as the ladder is raised or lowered. Extension booms are provided on port and starboard sides of the dredge hull. A winch and cable (or fluid operated cylinder) rigged to these extension booms swings the ladder through an arc as the ladder pivots about a gimbal attachment or universal joint on the dredge hull.
2. General Background of the Invention
Dredges are known that employ an elongated boom or ladder with an outer or distal end that is lowered to a water bottom. Equipment on the end of the ladder enables intake of slurried material to be removed. In such prior art dredges, movement of the ladder and its swing are limited, thus limiting digging depth and width. Swinging ladder dredges preferably use cylinders or winches to swing a short boom containing the slurry entrance (ladder) from side to side. The length of the ladder is constrained by the required excavation force and/or the ladder weight.
Patents have issued that are directed to dredge ladders. The following table lists some examples. Each patent in the table is incorporated herein by reference.
TABLEPat. No.TitleIssued5,791,074DredgeAug. 11, 19985,617,654Dredge Rotary Cutter HeadAug. 8, 19974,597,201Angled Boom Dredge System and Jul. 1, 1986Cutterhead Therefor4,445,290Appliance for Dredging the Bottom of a May 1, 1984Body of Water4,242,816Dredger Having a Two-Part BoomJan. 6, 19814,102,064Swell Compensator for Suction Dredging Jul. 25, 1978System3,956,834Dredge Ladder Shock Mounting May 18, 1976Arrangements3,821,589Dredge Ladder Shock Mounting Jul. 2, 1974Arrangements3,777,376Articulated Ladder Construction for Dec. 11, 1973Cutterhead Dredge3,763,580Apparatus for Dredging in Deep OceanOct. 9, 19733,739,503Hydraulic Dredge Having Articulated Jun. 19, 1973Ladder and Swell Compensator3,734,564Endless Bucket Dredge with Articulated May 22, 1973Ladder and Swell Compensator3,579,872Dredging Apparatus with Surge May 25, 1971Compensating Means3,146,537Floating Dredge DesignSep. 1, 1964